This invention generally relates to modular cargo containers, and more specifically to such cargo containers that are adapted to be mounted upon a highway truck-trailer chassis, a railway flat car or the like.
To reduce handling and to expedite loading and unloading operations, cargo is frequently shipped in bulk box-shaped containers that can be transported by and transferred between trucks, railroad cars and ships. For example, cargo may be initially loaded into such a cargo container at a factory, with the container mounted on, or subsequently mounted on, a truck chassis. The container may be carried over highways by the truck, transferred to a railroad car for further transportation, and then transferred back onto a truck, which may carry the container over highways to a final destination such as a warehouse or distribution center. Containers of this type usually are secured to a truck or railroad car frame by locking mechanisms that are mounted on the truck or railroad car frame and that engage complementary receiving mechanisms on the bottoms of the containers.
For many years, U.S. Government regulations limited the width of cargo containers that could be used in inter-state commerce to 96 inches, and cargo containers were commonly constructed with this width. Industry standards, referred to as ISO standards, were established for various dimensions of these cargo containers and for the truck and railroad car frames that were designed to carry these 96 inch wide containers. For example, ISO standards were established relating to the design and placement of the locking mechanisms used to secure the container to truck and railroad car frames, and the vast majority of locking mechanisms were constructed according to these standards.
Recently, U.S. Government regulations were changed to permit containers having widths of 102 inches to be used in inter-state commerce. It would, of course, be highly desirable to construct these new, wider containers so that they may be secured to truck or car railroad frames having locking mechanisms constructed according to conventional ISO standards. Doing this is complicated by several factors, including the design of the containers and the specific design of the conventional locking mechanisms.
To elaborate, these cargo containers--both the new 102 inch wide containers and the standard 96 inch wide containers--usually comprise a box-shaped housing or body having four vertical support posts and four bottom support plates. Each of these vertical support posts is located at a respective one of the corners of the container body, or on a side of the container adjacent a respective one of the container corners, and each bottom support plate is secured to a bottom of a respective one of the vertical support posts of the container. When a container is seated on a supporting member, the bottom support plates may be the principle, if not the only, part of the container that contacts the supporting member. Substantially the entire weight of the container may be transferred downward from its vertical support posts, to the bottom support plates and then to the supporting member; and because of this, the bottom support plates are positioned directly below the vertical support posts of the container. These bottom support plates are also the parts of the container that are directly attached to a supporting member such as a truck or railroad car frame.
More specifically, these containers are locked to a truck frame by locking mechanisms normally comprising a set of twist or lock arms that extend upward from the floor of the truck frame. When a cargo container is placed on such a truck frame, each of these twist arms extends into and is then locked in a bottom opening formed by a respective one of the bottom support plates of the container. Under ISO standards, laterally opposite twist arms on a truck frame are spaced apart approximately 89.5 inches, which is approximately the same distance between the bottom openings of laterally opposite bottom support plates of standard 96 inch wide containers. When standard bottom support plates are used on 102 inch wide containers, however, the bottom openings of laterally opposite bottom support plates are too far apart to receive laterally opposite twist arms of a truck frame that are spaced apart the standard 89.5 inches.
Also, these cargo containers are secured on a railroad car frame by locking mechanisms that often comprise a multitude of pedestals that extend upward from a floor of the frame. When a container is placed on a railroad car frame, each bottom support plate of the container is seated on a respective one of these pedestals. Each of these pedestals, in turn, includes a horizontal support surface, on which a bottom support plate of the container directly seats, and a latch that is inserted into an opening in the side of the bottom support plate. Each of these pedestals further includes a pair of vertical flanges that extend upward from the horizontal support surface of the pedestal; and in use, these vertical flanges extend around and immediately outside of the container corner to hold the container against lateral and longitudinal movement.
For instance, a container may be placed on a railroad car frame with the front right bottom corner and the front left bottom corner, respectively, on first and second laterally opposite pedestals. Each of these pedestals include a front vertical flange that is located immediately forward of the front of the container, and each of these pedestals also includes a side vertical flange that is located immediately outside the right and left sides, respectively, of the container.
According to ISO standards, the side vertical flanges of laterally opposite pedestals are approximately 96 inches apart, so that a cargo container may be located between these side vertical flanges in a close fit therebetween. When conventional bottom support plates are used on 102 inch wide containers, these side vertical flanges prevent laterally opposite bottom support plates of the container from seating directly on the horizontal supporting surfaces of laterally opposite pedestals.